Maximum response prediction of base-isolated structure with a slip-type damper system preventing excessive displacement

Abstract

Securing the stability of seismic isolation structures under extreme loads is one of the challenges for countries located in earthquake-prone areas. In Japan, large-scale earthquake predictions exceed the maximum target level set in existing building codes. During large-scale earthquakes, seismic isolation structures can excessively deform, resulting in unexpected damage, such as collisions between buildings and retaining walls. This study presents the development and applicability of a new steel damper system that can be used as a seismic isolation device for large-scale earthquakes. The proposed damper system consists of a circular hollow section steel damper welded to the upper and lower endplates and a bearing frame that covers the upper endplate. The lower endplate was fixed, and a horizontal force was transmitted to the circular hollow section damper in three different states: initial, slip, and bearing. The maximum displacement response was obtained using a seismic response evaluation based on the energy balance method by installing the new damper system as a base-isolated layer composed of an isolator and steel damper. The results indicated that the new damper system significantly reduced the seismic response during large-scale earthquakes.